This invention relates to a distribution type fuel injection pump of the type which distributes the fuel under pressure by rotating and reciprocating a plunger.
The distribution type fuel injection pump has a construction as disclosed, for example, in U.S. Pat. No. 4,346,688, and the characteristic line of the revolutions per minute (r.p.m.) of the engine and the amount of the fuel injected is the characteristic illustrated with a thick line in FIG. 2, and when the engine is in a low speed rotation condition, the characteristic an excess fuel starting device begins to appear at the idle spring and the start spring, and the increased amount of fuel at start time occurs, and the start of the engine is arranged to be carried out easily.
However, the characteristic of an excess fuel starting device always functions when it reaches a value below a certain r.p.m. even after the engine is once started, and as shown in FIG. 2, when the accelerator pedal is shifted rapidly from an idle lever position (at idle time) to a full load lever position, the fuel is increased rapidly from A to B, resulting in the supply of an excessive amount of fuel, and the smoke starts to generated due to the deterioration of the air/fuel ratio. However, the elimination of the characteristic of the excess fuel starting device results in the deterioration in the engine starting property, which leads to lots of problems, and which does not become an effective trouble shooting means for the prevention of the smoke.